I'm controlling boost with the EMS currently but its not very consistent and I want to swap in an MBC.

Is there anything I have to change in the tune after I install the MBC? I think I just have to "uncheck" Boost W/G Output in the boost control options menu to disable it. But i'm not 100% sure.

Any input?

 

how did you go about generating your base pc duty map? if you havent generated a base duty map first, i can see how boost control might be bad & inconsistant.

i have read that the stock boost solenoid is crap, but my experience with my oem solenoid is ok.....

 

I didn't. Ivey tuned it. He suggested I pick up a MBC because there was difficulty controlling the boost at first. Since I have one sitting around i'm gonna give it a shot.

 

Man I had the same problem with mine. All you need to do is install a mbc like you would normally. take the vacuum hoses off the electronic solenoid and run them to the mbc and then to the wastegate. Then go out and set it with a boost guage or use a laptop to monitor the boost.

 

Which solenoid are you using?

 

boost control with the AEM works best with the GM solenoid. I think Perrin makes a solenoid that you replace the stocker with too...

 

I'm using the GM solenoid.

Theres a possibility it could be a boost leak too. I pressure tested the system and found a couple. I fixed them and tried to test it again but when it got to about 21 psi the homemade PVC tester just popped right off the turbo. No leaks up to that point but I can't be sure about any leaks beyond that.

I have it tuned for 30-31psi. I can do a 3rd gear pull and it'll hold 30 psi to redline. Then do another 3rd gear pull a minute later and it won't hold more then 23psi. Then another one and it won't boost any higher then 27psi. But it always holds the boost, it doesn't taper off. That makes me think its the boost control. We'll see. I'm going to try the MBC this afternoon.

 

I have simular oddities that are driving me nuts. Soon as I get a nice flat boost line it creeps, then it's a little on the low side, then it's perfect.

 

I used the apex AVCR selenoid - its very heavy duty. Works great.

 

Actually, it's been known to leak past 15#'s. The AEM Boost Solenoid works great, heavy duty like the Apex'i, and comes with many fittings for your application(Barb fittings or AN fittings).

 

What are your settings for the closed loop boost control? Are you using boost based on VSS?

 

Thanks for the help. The MBC fixed the problem. My logs show boost fluctuating slightly but not too bad. It stays between 29.5 and 30.5 psi. Its a lot smoother now and my boost gauge isn't dancing around under load.

 

Apart from all the boost issues - how did you like his tune?

 

Wouldn't go to anyone else. I think he did an awesome job considering all that was wrong with the car. The solenoid was obviously a problem, but when he was tuning it the car had 4 seperate boost leaks on top of that. Now that everything is all buttoned up i'm gonna go back so he can do a C16 tune.

 

I have the same problem, and my tuner made me replace the wastegate... but i doubt that it's the problem, so how exactly did you fix it? You're using the mbc now? I'm using hks evc, i hope it's just vacuum leaks... you guys ever had to deal with broken stock wastegate after around 2-3 years of driving your evo?